Electronegativity and bonding
Cambridge A-Level Chemistry (9701) · Unit 3: Chemical bonding · 8 flashcards
Electronegativity and bonding is topic 3.1 in the Cambridge A-Level Chemistry (9701) syllabus , positioned in Unit 3 — Chemical bonding , alongside Ionic bonding, Metallic bonding and Shapes of molecules. In one line: Electronegativity is the power of an atom to attract the electron density in a covalent bond towards itself.
Marked as AS Level: examined at AS Level in Paper 1 (Multiple Choice), Paper 2 (AS Structured Questions) and Paper 3 (Advanced Practical Skills). The same content may also be assumed in Paper 4 (A Level Structured Questions).
The deck below contains 8 flashcards — 1 definition, 6 key concepts and 1 calculation — covering the precise wording mark schemes reward. Use the definition card to lock down command-word answers (define, state), then move on to the concept and calculation cards to handle explain, describe, calculate and compare questions.
Electronegativity
Electronegativity is the power of an atom to attract the electron density in a covalent bond towards itself.
What the Cambridge 9701 syllabus says
2025-2027 syllabus, in our words · AS LevelWhat the syllabus expects you to be able to do in this topic, in plain English. For the exact wording, see the official syllabus (PDF).
- Define electronegativity as an atom's power to attract electrons towards itself.
- Explain how the electronegativity of an element depends on its atomic radius, its nuclear charge and the shielding provided by inner shells and inner sub-shells.
- State and explain how electronegativity changes down a Periodic Table group and along a period.
- Use the difference in Pauling electronegativity between two atoms to predict whether ionic or covalent bonding will form (Pauling values are provided where needed; the partial covalent character shown by some ionic compounds is not assessed).
Cambridge syllabus keywords to use in your answers
These are the official Cambridge 9701 terms tagged to this section. Mark schemes credit responses that use the exact term — weave them into your answers verbatim rather than paraphrasing.
Define electronegativity.
Electronegativity is the power of an atom to attract the electron density in a covalent bond towards itself.
Explain how nuclear charge affects electronegativity.
A greater nuclear charge (more protons) leads to a stronger attraction for electrons, thus increasing electronegativity. The positive charge of the nucleus is more effective at attracting electrons.
Explain how atomic radius affects electronegativity.
A larger atomic radius means the valence electrons are further from the nucleus, experiencing weaker attraction. This decreases the atom's ability to attract electrons in a bond, thus reducing electronegativity.
Explain how electron shielding affects electronegativity.
Increased shielding from inner electron shells reduces the effective nuclear charge felt by valence electrons. This weakens the attraction for electrons in a bond, thus decreasing electronegativity.
State the trend in electronegativity across a period of the Periodic Table, and explain why.
Electronegativity generally increases across a period (left to right). This is because nuclear charge increases while shielding remains relatively constant, leading to a stronger attraction for bonding electrons.
State the trend in electronegativity down a group of the Periodic Table, and explain why.
Electronegativity generally decreases down a group. This is because atomic radius and shielding increase, reducing the effective nuclear charge felt by bonding electrons and thus weakening the attraction.
Using Pauling electronegativity values, how can you predict whether a bond will be ionic or covalent?
A large difference in electronegativity (typically > 1.7) between two atoms indicates a likely ionic bond, where one atom strongly attracts the electrons from the other. A small difference indicates a covalent bond with shared electrons.
Given the Pauling electronegativity values of Na (0.93) and Cl (3.16), predict the type of bond formed between them.
The electronegativity difference between Na and Cl is 3.16 - 0.93 = 2.23, which is greater than 1.7. Therefore, a strong ionic bond is predicted.
More Chemistry flashcards
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All Chemistry FlashcardsMore topics in Unit 3 — Chemical bonding
Electronegativity and bonding sits alongside these A-Level Chemistry decks in the same syllabus unit. Each uses the same spaced-repetition system, so progress in one informs the next.
Key terms covered in this Electronegativity and bonding deck
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